The concept of generating and communicating with noise codes of the type termed code mates having correlation functions which upon detection provide an impulse autocorrelation function is generally known and shown, for example, in U.S. Pat. No. 3,519,746, entitled, "Means And Method To Obtain An Impulse Autocorrelation Function", which issued to Frank S. Gutleber, the present inventor, on July 7, 1970. Other examples include U.S. Pat. No. 3,634,765, entitled, "System To Provide An Impulse Autocorrelation Function Upon Linear Addition . . . " which issued to Frank S. Gutleber on Jan. 11, 1972, and U.S. Pat. No. 4,293,953, entitled, "Bi-Orthogonal PCM Communication System Employing Multiplexed Noise Codes", which issued to Frank S. Gutleber on Oct. 6, 1981. It is to this type of apparatus to which the present invention is generally directed.
Accordingly, it is an object of the present invention to provide an improvement in the generation and utilization of noise codes in communications systems.
Another object of the invention is to provide an improvement in bi-orthogonal pulse code modulation communications systems.
Still another object is to provide an improvement in noise code communications systems employing bi-orthogonal noise code mate pairs having autocorrelation functions which upon detection in a matched filter compress to an impulse.
These and other objects are achieved by a bi-orthogonal pulse code modulation communications system employing noise code mate pairs comprising a pair of bi-polar digital noise code mates which are impressed on respective RF carriers generated by the same frequency source with one code mate being transmitted separately as a vertically polarized wave while the other code mate is transmitted separately as a horizontally polarized wave and whereupon the orthogonally polarized RF carrier waves containing the code mates are respectively received by horizontally and vertically polarized antennas coupled to receiver apparatus which provides received signals containing the code mates, which signals are then fed to their matched filters which in turn operate to compress the code mates, the compressed code mates being furthermore fed to a linear adder which provides a compressed lobeless impulse output signal.